JP2003128299A - Sheet conveyance apparatus, image reader, and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveyance apparatus capable of delivering sheets without upsetting page sequence, and an image reader, and an image forming device. SOLUTION: In conveying sheets starting from the one on the bottom n, part of the sheet ((n-1)th sheet in Fig. 9 (c)) where the page sequence of image information is early is overlapped on the image information forming surface side of the sheet ((n)the sheet in Fig. 9 (c)) where the page sequence of the image information shown in Fig. 9 (c) is late, and, by reversing and delivering the sheets, proper page sequence is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying device, and is applied to an image reading device for reading a document image and an image forming device for forming an image on a sheet.

[0002]

2. Description of the Related Art Conventionally, an original document is applied to an image reading apparatus of a system in which two sheets are superposed on a platen and the exposure system is scanned to read image information on the sheets. There was a device.

In order to superimpose a part of two sheets, first, the first sheet is fed, the sheet is temporarily stopped before reaching the image reading position, and the stopping position is accurately determined. By feeding the second sheet and stopping it, the overlap amount of the two sheets was set, and then the two sheets were simultaneously conveyed.

[0004]

However, in the case of the prior art as described above, the direction in which the sheets are overlapped is uniquely limited by the configuration of the sheet path, and there are differences in modes and the like. There is a drawback in that it is not possible to set the overlapping direction that matches the configuration of the discharge port.

Consider, for example, a sheet conveying device capable of separating originals from either the upper or lower direction. When the originals are fed by upper separation and the image information is read from the first page, the original page order at the time of ejection is disturbed. In order to avoid this, a system that discharges straight without inversion is conceivable. In this case, if the originals are to be ejected while allowing the overlapping, the overlapping shown in FIG.

On the other hand, when a bundle of originals is conveyed downward and the image information is read from the last page, in the same overlapping manner as described above, as shown in FIG. 9B, it may be reversed or not. No matter which direction the paper was ejected, the order of the originals at the time of ejection was incorrect.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to discharge a sheet without causing a page order error, an image reading apparatus and an image reading apparatus. To provide a forming apparatus.

[0008]

In order to achieve the above object, in a sheet conveying apparatus of the present invention, a sheet conveying apparatus for separately feeding and discharging a sheet bundle stacked in page order one by one, When feeding two sheets in series as a unit from the last page, the page order overlaps the front side of the latter sheet and the page order partially overlaps the back side of the first sheet. It is characterized in that they are conveyed in an overlapped state.

It is preferable to provide a feeding means for feeding from the last page of the bottom of the stack of sheets stacked in page order, and an ejecting means for inverting the sheet and ejecting it with its front side up.

There are two conveying paths for joining the separated and fed sheets in the latter half of the conveyance, and a selection means for selecting one of the conveying paths is provided. Before approaching, it is preferable that the leading edge of the sheet that has been fed later is conveyed to the merging portion and the sheets are superposed.

One of the two suction-conveying means having a long rear side is provided on both sides of the sheet, and the sheet fed first is conveyed by the suction-conveying means having a long rear side, and the sheet fed later is conveyed. It is preferable that the sheet is conveyed by the other sucking and conveying means, and then the suction of the other sucking and conveying means is stopped to stack the sheets.

The image reading apparatus of the present invention is characterized by including the above-mentioned sheet conveying apparatus and an image reading means for reading image information of a sheet conveyed by the sheet conveying apparatus.

The image forming apparatus of the present invention is characterized by including the above-mentioned image reading apparatus.

It is characterized in that it is provided with the above-mentioned sheet conveying device and an image forming means for forming an image on a sheet conveyed by the sheet conveying device.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions of the components described in this embodiment,
Unless otherwise specified, the material, the shape, the relative arrangement, and the like are not intended to limit the scope of the present invention thereto.

(First Embodiment) The first embodiment will be described with reference to FIGS.

(Description of Apparatus) Referring to FIG. 1, a document feeder 2 has a document tray 4, and a document P as a sheet on the document tray 4 is sequentially separated from its uppermost sheet, and a copying machine is provided. The sheet is conveyed onto the platen glass 3a which is the reading unit of the main body 1, or sequentially separated from the bottom sheet and conveyed.

The copying machine main body 1 is composed of an image input section (hereinafter referred to as a reader section) 200 and an image output section (hereinafter referred to as a printer section) 300.

The reader unit 200 moves or fixes the image reading means to read the image information of the document P.

The printer section 300 forms an image on a recording material fed by an electrophotographic image forming means. The image forming unit is composed of a photosensitive drum and a charger, an exposure device, a developing device, a transfer device, etc. arranged around the photosensitive drum. Since the electrophotographic image formation is conventionally known, the description thereof is omitted here.

(Description of Document Tray) Referring to FIG. 2, a pair of width direction regulating plates 42 are arranged on the document tray 4 so as to be slidable in the width direction of the document P.
The width direction of the document P set above is regulated to ensure the stability of the document P during feeding.

A stopper 21 which is rotated by a stopper solenoid 106 (see FIG. 7) is arranged at an end of the document tray 4, and a document P set on the document tray 4 is provided.
Is restricted by the protruding stopper 21 so that it cannot move downstream.

(Explanation of Arrangement of Various Sensors on Document Tray)
Referring to FIG. 2, a document set detection sensor 40 (40a, 40b) that is a transmissive optical sensor that detects that the document P is set is provided near the upstream portion of the stopper 21 in the transport direction.

A final document detecting sensor 41, which is a reflection type optical sensor, is provided in the middle of the document tray 4, and whether or not the document P being fed is the final document in the case of the uppermost separation. Can be detected.

Further, a document width detecting sensor (not shown) for detecting the length of the document P set on the document tray 4 in the width direction by detecting the position of the width direction regulating plate 42 of the document tray 4. It is provided at the bottom.

(Explanation of Separation Section) Referring to FIGS. 4, 5, and 6, as shown in FIG. 4, a swing arm 53 (57) is provided above the document tray 4 and is a rotation shaft of the separation feeding roller 8. Center C1
The front and rear support plates 51a (5
The arm shaft 51c penetratingly supported by 1b) regulates the swing. The paper feed roller 5 is provided at the tip of the swing arm 53 (57).

Normally, the paper feed roller 5 is regulated by the arm shaft 51c so as to be retracted above the separation upper guide plate 52 (home position) so as not to interfere with the document setting work. The lifting arm 51 is used for the lifting motor 1
03 (FIG. 7), it is held in the position of FIG.

Further, the elevating arm 51 has a rotation axis center C1.
It is possible to move up and down from the position shown in FIG. 4 to the position shown in FIG.

As shown in FIG. 6, the paper feed roller 5 is provided at the tip of a swing arm 53 (57) which rotates around the center C1 of the rotary shaft. The swing arm 53 (57) falls by its own weight as the lift arm 51 moves up and down, and the paper feed roller 5 lands on the document P and stops. In this state, by rotating the paper feed roller 5, the stacked originals can be fed in order from the top.

In the vicinity of the downstream side of the stopper 21 in the carrying direction,
There is provided a separation section including a known separation belt 6 and separation feed roller 8, and the separation operation is performed by rotating the separation section in the direction of the arrow in FIG.

On the other hand, below the document tray 4, there is provided a paper feed roller 5'for feeding the document P from the bottom sheet. The paper feed roller 5 ′ has a support mechanism (not shown),
Similar to the paper feed roller 5, a position that is not normally exposed is arranged as a home position, and when the document P is fed from the bottom sheet, it abuts on the bottom sheet of the stacked documents and the stacked documents are fed in order from the bottom. It is possible.

In the case of feeding from the lowermost sheet, the separating portion including the well-known separating belt 6 and separating feeding roller 8 is rotated in the opposite direction of the arrow in FIG.

(Description of Conveyance Path) Referring to FIG. 3, document feed paths (a) and (b) branching and joining (c) and (d) are formed from the document tray 4 to the platen glass 3a. The feeding paths (a), (b), (c), and (b), (b), and (d) are bent to connect to the document reading path (e) on the platen glass 3a, and the document P is placed on the platen glass 3a. Transport to.

The original P on the platen glass 3a passes through the original reading path (e) and the original discharge path (to) while the image is being read, and is placed on the discharge tray 10 or the reverse discharge tray 10 '. Is discharged.

(Explanation of Roller Arrangement) Referring to FIG. 3, the original feeding path (a) is a feeding path in which the original P separated by the separating portion is fed in the downstream direction by the separating belt 6 or the separating feeding roller 8. It is a road.

A first feeding roller pair 16 is provided between the document feeding paths (a) and (b) to restrain the document P fed from the separating section so that the document is separated by the separating section. The skew of P is prevented.

Further, the separation belt 6 and the separation feeding roller 8
Is provided with a one-way mechanism, and the original P is
The feeding roller pair 16 reduces the load when the sheet is pulled out from the separating section.

A second feeding roller pair 9 is provided between the original feeding path (b) and (c) or (d).
The feed roller pair 9 forms a loop on the original P that has arrived, and corrects the skew of the original P.

A first reading roller pair 37 is provided near the upstream portion of the document reading path (e), and a second reading roller pair 38 is provided near the downstream portion.
Is provided and the original P being read is brought into close contact with the platen glass 3a to prevent image distortion of the output paper due to floating of the original P.

A pair of discharge rollers 12 is provided in the document discharge path (to).
Is provided, the image reading is completed, and the conveyed document P is discharged onto the discharge tray 10 or the reverse discharge tray 10 ′.

Further, the conveying force by the paper discharge roller pair 12 is set to be low, and when the document P is nipped between the second reading roller pair 38 and the paper discharge roller pair 12, the document is discharged by the paper discharge roller pair 12. P slips.

(Explanation of the flapper in the path) See FIG. 3. A feeding flapper 22 is provided in the vicinity of the downstream side of the second feeding roller pair 9 in the conveying direction, and a document feeding path (c) and (d) are provided. ) Is switching. When the document P is fed to the document feeding path (C), it is at the solid line position in the figure, and when the document P is fed to the document feeding path (D), it is at the broken line position in the figure. It is designed to switch.

(Explanation of Sensor Arrangement in Path) See FIG. 2. A separation sensor 30 which is a transmissive optical sensor is provided between the separation feeding roller 8 and the first feeding roller pair 16 to separate them. The document P fed by the unit can be detected.

A skew detection sensor 31, which is also a transmissive optical sensor, is provided at the same position in the transport direction as the separation sensor 30 and at a position separated by a certain distance in the thrust direction. The skew amount of the document P fed in can be detected.

A pre-registration sensor 35, which is a transmissive optical sensor, is provided near the upstream portion of the second feeding roller pair 9, and the original feeding paths (a), (b), and (c) or The leading edge and the trailing edge of the document P passing through (d) can be detected.

In the vicinity of the downstream portion of the second feeding roller pair 9, the post-registration sensor 3 which is also a transmissive optical sensor.
9 is provided, and a reading start signal of the original P is output to the copying machine main body by detecting the leading edge of the original P.

A discharge sensor 34, which is a transmissive optical sensor, is provided in the vicinity of the downstream side of the pair of discharge rollers 12 in the transport direction, and the document is transported from the platen glass 3a to the document discharge path (to). P can be detected.

(Description of Drive System) See FIG. 7 FIG. 7 shows a drive system diagram of a motor, a clutch and a solenoid for driving each roller and flapper. Reference numeral 100 denotes a separation motor, and here, a DC motor is used. The separation motor 100 drives the first feeding roller pair 16.

A separation clock plate 100a consisting of a plurality of slits is provided on the motor shaft of the separation motor 100. When the separation motor 100 is rotated by the slits and the separation clock sensor 100b which is a transmission type optical sensor. , A clock pulse that is proportional to the number of rotations of the motor is generated.

Reference numeral 101 denotes a feeding motor, which is a stepping motor here. This feeding motor 1
01 drives the second feeding roller pair 9.

A feed clock plate 101a consisting of a plurality of slits is provided on the driven roller shaft of the second feed roller pair 9, and the slits and the feed clock sensor 101b, which is a transmission type optical sensor, allow When the feeding motor 101 rotates, a clock pulse proportional to the rotation speed of the motor is generated.

If a slip occurs while the document P is being fed by the second feeding roller pair 9, the slip amount can be calculated from this clock pulse number and the driving clock number of the feeding motor 101. It is like this.

A reading motor 102 is a stepping motor. This reading motor 1
Reference numeral 02 drives a first reading roller pair 37 and a second reading roller pair 38 which are reading units.

The reading motor 102 also transmits the drive from the second reading roller pair 38 to the paper discharging roller pair 12, and the discharging speed of the paper discharging roller pair 12 is the platen glass 3a.
The speed is increased so that the reading speed of the upper original P is higher.

Reference numeral 103 denotes a lift motor capable of rotating in the forward and reverse directions, and here, a stepping motor is used. The lift motor 103 drives a lift arm 51 (FIG. 4) that swings the paper feed roller 5.

Reference numeral 104 denotes a separation clutch, which transmits the drive of the separation motor 100 to the sheet feeding roller 5, the separation belt 6 and the separation feeding roller 8.

Reference numeral 105 denotes a flapper solenoid, which drives the feeding flapper 22. The feeding flapper 22 is switched to the solid line position when the flapper solenoid 105 is off, and to the broken line position when the flapper solenoid 105 is on.

Reference numeral 106 denotes a stopper solenoid, which drives the stopper 21. The stopper 21 is switched to the solid line position when the stopper solenoid 106 is off, and to the broken line position when the stopper solenoid 106 is on.

Next, the operation of the document feeder 2 will be described.

(Explanation of Separation Operation) Referring to FIGS. 2 and 3, when the original set detection sensor 40 detects the original P set on the original tray 4, the pre-separation operation is started and the paper feed roller is started. 5 descends and lands on the document P and stops, or the paper feed roller 5 ′ rises and abuts below the document P and stops.

In the following description, the originals P stacked on the original tray 4 will be referred to as original P1, original P2, original P3, ... If no particular order is specified, the original P is used. The operation of the paper feed roller 5 will be described below as a representative. When the copy condition is input on the operation unit of the copying machine body 1 and the start key is pressed, the stopper 21 is pressed.
Is rotated by the stopper solenoid 106 (FIG. 7),
The path of the document P is released. Then, the original P is advanced to the downstream portion in order from the original P1 which is the uppermost paper by the paper feed roller 5.

A separating / feeding roller 8 and a separating belt 6 which constitute a separating portion are provided downstream of the stopper 21, and rotate in the directions of the arrows in FIG. The incoming originals P are separated one by one and fed further downstream.

The original P that has passed through the separation unit is separated by the separation sensor 3
0, after the skew detection sensor 31 detects the skew amount, the skew is detected by the first feed roller pair 16 and further fed to the downstream portion.

When the document P is fed by the first feeding roller pair 16, the paper feeding roller 5 moves up to the position shown in FIG. Then, the separation clutch 106 (FIG. 7) is turned off,
The driving of the separation belt 6 and the separation feeding roller 8 is separated and stopped. Further, since the separating / feeding roller 8 is provided with the one-way mechanism, the separating / feeding roller 8 is rotated (rotated) following the movement of the document P being fed.

At this time, the original P is fed only by the first feeding roller pair 16 and is abutted against the nip portion of the stopped second feeding roller pair 9 to perform the well-known skew feeding correction. Be seen.

(Explanation of Overlap Transport Operation) FIG.
3 and FIG. 8, when the skew feeding correction is completed, the first feeding roller pair 16 and the second feeding roller pair 9 start to rotate at the same time, but these roller pairs are set so that their conveying speeds match. Synchronous speed control.

When the originals P1 (P3, P5 ...) Of odd number of sheets are fed by these roller pairs, the flapper solenoid 105 (FIG. 7) is turned off, so that the feeding flapper 22 is shown by the solid line in the figure. Switch to the position, and the manuscript P for one sheet
1 enters the document feeding path (C).

When the trailing edge of the original P1 passes through the nip portion of the paper feed roller 5, the paper feed roller 5 descends again to prepare for the separation operation of the original P2 for two sheets.

The first reading roller pair 37 has a conveyance speed of the first feeding roller pair 9 before the document P1 enters.
The synchronous speed control is performed so as to match the transport speed of.

When the trailing edge of the document P1 passes through the nip portion of the first feeding roller pair 16, the separation clutch 106
(FIG. 7) is turned on, and the sheet feeding roller 5 starts the separating operation of the document P2. This state is shown in FIG.

Further, when the trailing edge of the document P1 passes through the nip portion of the second feeding roller pair 9, the second feeding roller pair 9 stops. Then, the original P1 is independently conveyed by the first reading roller pair 37, and the image information is read by the reading unit.

At the same time, the original P2 reaches the pre-registration sensor 35 when the second feeding roller pair 9 is suddenly accelerated after the separation operation is started by the paper feeding roller 5 and stopped. Controlled. Then, when the pre-registration sensor 35 is turned on by the document P2, the document P2 is abutted against the nip portion of the second feeding roller pair 9 which is stopped, similarly to the case of the document P1, and skew feeding correction is performed. Be done. This state is shown in FIG.

The post-registration sensor 3 is provided by the trailing edge of the original P1.
When the document P1 is conveyed for a certain distance after 9 is turned on,
Similar to the case of the original P1, the first feeding roller pair 16 and the second feeding roller pair 16
The pair of feeding rollers 9 start rotating at the same time.

When the originals P2 (P4, P6 ...) Of even-numbered sheets are fed by these roller pairs, the flapper solenoid 105 (FIG. 7) is on-controlled, so that the feeding flapper 22 of FIG. After switching to the broken line position, the document P2 enters the document feeding path (D).

The original P1 independently conveyed by the first reading roller pair 37 and the second reading roller pair 38 and the original P2 independently conveyed by the first feeding roller pair 16 and the second feeding roller pair 9 are: At the confluence of the document feeding paths (C) and (D) near the upstream portion of the first reading roller pair 37 in the transport direction, the trailing edge of the document P1 and the leading edge of the document P2 are transported so as to overlap each other. This state is shown in FIG.

Here, the original P2 is fed to the first feeding roller pair 16
And the original P when the feeding is started by the second feeding roller pair 9.
1 is L1 from the rear end of the original P2 to the leading end of the original P2, L2 is the distance of the original feeding path (C) (from the second feeding roller pair 9 to the first reading roller pair 37), and the original feeding path (ni ) (The distance between the second feeding roller pair 9 and the first reading roller pair 37) is L
3, when L2> L3, the trailing edge of the original P1 and the original P
Overlap amount of 2 (hereinafter referred to as overlap amount)
L4 is a distance represented by the formula of L4 = (L2-L3) -L1, and this value L4 is configured to be 0 or more. That is, L4 = (L2-L3) -L1 ≧ 0.

As a result, the original P1 and the original P2 are conveyed with the rear end of the original P1 and the front end of the original P2 overlapping each other, and the image information is read by the reading unit.
Then, when the trailing edge of the original P1 passes through the nip portion of the second reading roller pair 38, the original P1 is accelerated and conveyed by the paper ejection roller pair 12 and ejected onto the paper ejection tray 10. This state is shown in Figure 8.
It is shown in (d).

Further, the overlap amount L4 can be selectively controlled by arbitrarily changing the timing of starting feeding the original P2 by the first feeding roller pair 16 and the second feeding roller pair 9. . Further, the non-image forming portion such as the perforated portion or the blank portion of the original document P is formed in the area where the rear end of the original document P1 and the front end of the original document P2 are overlapped with each other, thereby eliminating the distance between the original document P1 and the original document P2. be able to.

Here, the overlapping manner, which is a characteristic part of the present invention, will be described.

The above-mentioned manner of overlapping P1 and P2 is a sheet in which P1 is 1 in FIG.
P2 corresponds to a sheet of 2.

In this case, if discharge is carried out as it is, P
The 1 or 1 sheet is discharged first with the image information facing downward, and the P2 or 2 sheet also overlaps the upper side of the P1 or 1 sheet with the image information facing downward, so the page order is out of order. There is no.

However, as shown in FIG. 9B, in the case of transporting from the bottom n sheets of a sheet bundle of n sheets, in the same overlapping manner as in FIG. Even so, the page order is out of order.

Therefore, when the sheet of the bottom n is conveyed, if it is overlapped as shown in FIG. 9C, it is reversed and ejected, so that the page order is secured.

9 (a) and 9 (c) are common in that the sheets of the image information in the page order come later (see FIG. 9).
9A is a sheet 2 and FIG. 9C is a sheet n, on the image information forming surface side, the sheet having the first page of the image information (FIG. 9A is sheet 1 and FIG. 9C). ) Is a part of n-1 sheets).

By this stacking method, the overlapped sheets can be discharged and stacked in a page order without waste without separating the overlapping sheets again.

9A to 9C have been described for the case where the image information is already present on the sheet and the page order is determined, the sheet is the transfer sheet and the overlap conveyance is performed. The same applies to the case where image information is formed on the sheet later.

Further, although the case where the image information exists on only one side of the sheet has been described above, the same method is used for the case where the image information exists on both sides of the sheet or is transferred. You can keep things in order.

(Explanation of Block Diagram of Control Circuit) See FIG. 10. FIG. 10 is a block diagram showing the configuration of the control circuit of the present embodiment. The control circuit is a microprocessor (CPU).
The input / output port of the CPU 201 is connected to drive circuits of various loads and sensor signals.

The control circuit uses a battery (not shown)
It has a RAM to be backed up and a ROM that stores control sequence software. Reference numeral 202 is a communication IC for controlling data communication with the copying machine main body 1. The separation motor 100 is driven and controlled by the driver 203 and the controller 203a, and the controller 2
A reference clock, an on / off signal, and the like, which serve as a reference of the motor rotation speed, are input from 03a to the CPU 03a.
The feeding motor 101 is drive-controlled by a driver 204. Similarly, the reading motor 102 also drives the driver 2
Drive control is performed by 05. A phase excitation signal and a motor current control signal are input from the CPU 201 to each driver. The lifting motor 103 is the driver 2
Drive control is performed by 06.

The motors 100 to 103 respectively have encoders 100a to 100a as means for detecting their rotation speeds.
103a and the detection means 100b-103b.

The driving of the separation clutch 104 is controlled by the driver 207.

The drivers 203 to 207 are all CP
The operation is controlled by the sensor signal connected to the input / output port of U201.

Further, various sensors such as a separation sensor 30, a skew detection sensor 31, a paper discharge sensor 34, a pre-registration sensor 35, a post-registration sensor 39, a document set detection sensor 40, a final document detection sensor 41, and a document width detection sensor 44. Is connected to the input port of the CPU 201 and is used to monitor the behavior of the document P and the behavior of the driving load in the apparatus. (Main Flow) See FIG. 11 Next, the operation of the present embodiment will be described based on the main flow shown in FIG.

The original set detection sensor 40 detects whether or not the original P is set on the original tray 4, and the operation is started by pressing the start key on the operation unit of the copying machine main body 1 (draftmd0). .

In order to lower the paper feed roller 5 onto the original P set on the original tray 4, the pickup DOW
N processing is performed (draftmd1), and then the separation processing (d
raftmd2) and feeding processing (draftmd3).

Further, a document flow reading process is performed in which the image of the document P is read by the reading unit of the copying machine main body 1 (dra
ftmd4), and then the separation sensor 30
Wait until the trailing edge is detected (draftmd5), the document set detection sensor 40 detects the break of the document P (draftmd6), and if the document is not the final document, the document P is placed on the discharge tray 10. In order to discharge the sheet to (draftmd8), (draftmd8),
Return to ftmd2) and repeat the same processing.

Further, in (draftmd6), if the document is the final one, the paper discharge process is performed (draft).
md7), after that, pickup UP processing is performed to raise the paper feed roller 5 to the home position (draft).
md9), a series of processing ends.

In this embodiment, the rear end of the two originals P1 and the front end of the original P2 are conveyed in a state of being overlapped with each other, and the image information is read by the reading unit of the copying machine main body 1. Convey as a set.

(Second Embodiment) In the first embodiment, the trailing edge of the preceding document and the leading edge of the following document are overlapped with each other by branching and joining the transport paths. In the second embodiment, a method of superposing the trailing edge of the preceding document and the leading edge of the following document on each other with another configuration will be described.

A second embodiment of the present invention will be described below with reference to the drawings.

FIG. 12 is a sectional view of the document feeding device 400, FIG. 13 is a detailed view of the feeding portion of the document feeding device 400, and FIG. 14 is an explanatory diagram of the operation of the feeding portion of the document feeding device 400.

In FIG. 12, the originals P advanced from the original tray 4 by the paper feed rollers 5 and 5'and separated and fed one by one by the separating portion composed of the separating belt 6 and the separating and feeding roller 8, The suction belt 40 driven by the suction motor M1 and given a suction conveyance force by the suction fan F1.
1, or the suction belt 40 driven by the suction motor M2 and given a suction conveyance force by the suction fan F2.
2, the sheet is fed to the reading section of the copying machine body 1 at the downstream side in the conveying direction. Specifically, as shown in FIG. 13, a plurality of pores are arranged on the endless belt surface and sucked inward so that the endless belt surface is sucked and fed.

The means for superimposing the trailing edge of the preceding document and the leading edge of the following document in this embodiment are provided by the above-mentioned feeding section, and the details thereof will be described below.

(Description of Document Overlay Processing) See FIG. 14 Suction belt 40 rotated by suction motors M1 and M2
The document P1 is adsorbed and fed to the side (upper side) of the suction belt 402, which has a longer rear side and operates the suction fan F2. This state is shown in FIG.

When the trailing edge of the document P1 reaches the predetermined position, the suction motor M2 is stopped while the document P1 is attracted to the suction belt 402, and at the same time, the suction fan F1 is driven to overlap the document P2. Prepare for the match. This state is shown in FIG.

After a predetermined period of time, the original P2 fed from the separating section has a suction force lower on the suction belt 402 side than on the suction belt 401 side (lower side) due to the original P1. Is adsorbed on and fed. This state is shown in FIG.

After a predetermined time, the suction motor M2 is re-driven, and the suction belts 401 and 402 jointly feed the two originals P1 with the trailing edge of the original P1 and the leading edge of the original P2 overlapping each other. After a predetermined time, the suction fan F1 is stopped,
The original P1 is delivered to the suction belt 402 side. This eruption is shown in FIG. 14 (d).

As a result, the original P1 and the original P2 are conveyed with the rear end of the original P1 and the front end of the original P2 overlapping each other, and the image information is read by the reading unit of the copying machine main body 1. In addition, it is possible to stack the trailing edge of the preceding document and the leading edge of the following document in a certain direction, and do not shorten or widen the distance between sheets by speed-up control, and eject and stack the originals without changing the order. It becomes possible to do.

[0109]

As described above, according to the present invention, by realizing the sheet overlapping direction in accordance with the separation mode and the configuration of the discharge port, the discharge can be performed without changing the page order while maintaining the overlap state. Therefore, it is not necessary to speed up the motor to eliminate the overlapped state, the cost is low, and the damage to the seat due to acceleration / deceleration can be suppressed.

By forming the overlap relationship by merging the sheets branched into a plurality of paths to each other, it is possible to save unnecessary time such as switchback and temporary stop, and to reduce the time required for overlapping. You can maximize productivity by making the most of it.

Further, since the overlap amount can be stabilized only by controlling the path length of the branch path and the sheet interval immediately after separation, the accuracy of image information transmission is improved, and the variation in transport performance is reduced. As a result, stabilization can be achieved.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an image forming apparatus provided with a document feeder according to a first embodiment.

FIG. 2 is a schematic cross-sectional view showing a document feeder according to the first embodiment.

FIG. 3 is an explanatory diagram illustrating a transport path of the document transport device according to the first embodiment.

FIG. 4 is an explanatory diagram showing an operation of a separation unit of the document feeder according to the first embodiment.

FIG. 5 is an explanatory diagram showing an operation of a separating unit of the document feeder according to the first embodiment.

FIG. 6 is an explanatory diagram showing the operation of the separating unit of the document feeder according to the first embodiment.

FIG. 7 is an explanatory diagram showing a drive system of the document feeder according to the first embodiment.

FIG. 8 is an explanatory diagram showing a flow of a document in the document conveying device according to the first embodiment.

FIG. 9 is an explanatory diagram showing stacking of documents in the document transport device according to the first embodiment.

FIG. 10 is a block diagram showing a configuration of a control circuit of the document feeder according to the first embodiment.

FIG. 11 is a flowchart showing a main flow of the document feeder according to the first embodiment.

FIG. 12 is a cross-sectional view showing a document feeder according to a second embodiment.

FIG. 13 is a perspective view showing details of a feeding unit of the document feeder according to the second embodiment.

FIG. 14 is an explanatory diagram showing an operation of a feeding unit of the document feeder according to the second embodiment.

[Explanation of symbols]

1 Copier body 2 Document feeder 3a Platen glass 4 Original tray 5,5 'paper feed roller 6 separation belt 8 Separate feeding roller 9 Second feeding roller pair 10 Output tray 10 'reverse output tray 12 Output roller pair 16 1st feeding roller pair 21 Stopper 22 Feeding flapper 37 First Reading Roller Pair 38 Second reading roller pair 200 Reader unit 300 Printer section 400 Document feeder 401, 402 suction belt

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Katto Katoh             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Katsuaki Hirai             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Tomohito Nakagawa             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Shinsuke Ubayashi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation (72) Inventor Kazuhiko Ishiwata             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F-term (reference) 2H076 BA17 BA18 BA28 BA35 BA42                       BA63                 3F049 AA01 EA23 FB01 LA01 LA11                       LB02                 3F101 LA01 LA11 LB02                 3F343 FA03 FB01 FC03 GA02 GB01                       GB02 GC01 GD01 JA01 KB05                       KB06 MA03 MA15 MA36 MB03                       MB13 MC06 MC23

Claims (7)

[Claims] 1. A sheet conveying device for separately feeding and discharging a sheet bundle stacked in page order one sheet at a time, and when feeding a set of continuously conveyed two sheets as a unit from the last page. A sheet conveying apparatus, which conveys a sheet in a page order in which the sheet in the rear side is overlapped with a portion in the back side of the sheet in the page order overlapping. 2. A feeding means for feeding from the last page of the bottom of a sheet bundle stacked in page order, and an ejecting means for inverting the sheet and ejecting it with its front side up. The sheet conveying device according to claim 1. 3. A separation means is provided which has two conveyance paths that join together in the latter half of the conveyance of the separately fed sheets, and has a selection means for selecting one of the conveyance paths, and the trailing end of the sheet fed earlier is 3. The sheet conveying apparatus according to claim 1, wherein the leading edge of the sheet that is fed later is conveyed to the confluence portion and the sheets are superposed on each other before the sheet reaches the confluence portion. 4. A sheet is provided with two suction conveyance means having a long rear side on either side of the sheet, and the sheet previously fed is conveyed by the suction conveyance means having a long rear side and then fed. 3. The sheet conveying apparatus according to claim 1, wherein the sheet is conveyed by the other suction conveying means, and then the suction of the other suction conveying means is stopped to stack the sheets. 5. A sheet conveying device according to claim 1, and image reading means for reading image information of a sheet conveyed by the sheet conveying device. Image reading device. 6. An image forming apparatus comprising the image reading device according to claim 5. 7. A sheet carrying device according to claim 1, and an image forming means for forming an image on a sheet carried by the sheet carrying device. Image forming apparatus.